A cobpobation ob



UNITED STATES PATENT OFFICE.

RADCLYFFE FUBNESS, OF J'ENKINTOWN, PENNSYLVANIA, ASSIGNOR TO THE MID-VALE STEEL COMPANY, OF PHILADELPHIA, PENNSYLYANIA, A CORPORATION OFPENNSYLVANIA.

HIGH-SPEED-TOOL-STEEL ALLOY.

1 ,233,862 Specification of Letters Patent.

No Drawing.

To all whom it may concern:

Be it known that I, RADOLYFFE FURNESS, a citizen of the United States,residing at Jenkintown, county of Montgomery, and State of Pennsylvania,have invented a new and useful Improvement in High-Speed- Tool-SteelAlloys, of which the following is a full, clear, and exact description.

The object of my invention is to produce a new. and improved high speedtool steel having a cutting efliciency superior to tool steels of ananalogous character.

I have discovered that when to steel is added both cobalt and uranium,especially when these are associated with tungsten, chromium andvanadium, a substantial increase in cutting efliciency is attained.

I prefer an alloy of steel containing about 4.5% of cobalt, about .7 ofuranium, about 13.5% of tungsten, about 3.5% of chromium,

and about 1.5% of vanadium. The carbon of the steel should constituteabout .7% of the entire alloy. The steel may contain the usualproportions of manganese, phosphorous, silicon and sulfur.

It is preferred to add the-uranium in the crucible or in the ladle.

. It is found that the addition of uranium, when cobalt also is added,improves the quality of the steel even though only a relatively smallproportion of the uranium actually added is found to remain in thefinished product. Such an alloy, therefore, in which the ercentage ofuranium remaining in the finis ed product is as low as .10% is withinthe scope of my invention, although the percentage of uranium may beincreased to as much as'2%.

The cobalt may range between 3 and 7% and the tungsten between 12 and20%; although if, as is known, cobalt in part displaces the tungsten,the cobalt may be increased as high as 15 or 20%, while the tungsten maybe reduced as low as 9%. The chromium should be between 3 and 4%,although it may range from 2 to 6%. I' add vanadium to obtain the wellknown qualities Application filed March 12, 1917. Serial No. 154,134.

which vanadium. imparts to the alloy, if those qualities are desired,the amount ranging from .50 to 2 per cent.

The carbon may vary from .5' to .9 per cent.

Where in the claims I refer to the ordinary high speed tool steeladditions, I mean to include one or more of those specified, namely:tungsten, chromium and vanadium, or their known substantial equivalents.

It will be understood that the preferred proportion of uranium added isso small that it cannot accurately be said to in part replace the knownhi h speed tool steel additions, such as coba t and tungsten, thesebeing used in substantially the same proportions as heretofore, theaddition of uranium,

even in an apparently negligible proportion, having been discovered byme to improve the cutting efiiciency of high speed tool steels providedthey contain cobalt.

Havin now fully described my invention .what I esire toclaim and protectby Letters Patent is:

1. A high speed tool steel containing uranium, cobalt and the ordinaryhigh speed tool steel additions.

2. A high speed tool-steel alloy containing uranium, cobalt, tungstenand chromium.

3. A high speed tool-steel containing uranium, cobalt and tun en.

4. A high speed tool-steel containing uranium .10 to 2%, cobalt 3 to 20%and the ordinary high speed tool steel additions.

5. A high speed tool-steel containing uranium .10 to 2%, cobalt 3 to 20%and tungston 9 to 20%.

6. A high speed tool-steel containing uranium .10 to 2.%, cobalt 3 to20%, tungsten 9 to 20% and chromium 2 to 6%.

In testimony of. which invention, I have hereunto set my hand, atPhiladelphia, on this 8th day of March, 1917.

RADCLYFFE FURNESS. Witnesses:

J osnrn Enrw-rsnn, HARRY D. Smornruo.

